DE10210124A1 - Polymer mixtures with improved odor control - Google Patents

Abstract

The present invention relates to polymer mixtures including hydrogel-forming polymers capable of absorbing aqueous fluids and prepared by polymerization of olefinically unsaturated carboxylic acids or derivatives thereof together with copolymers of C<SUB>2</SUB>-C<SUB>8 </SUB>olefins or styrenes with anhydrides and also their preparation, use and hygiene articles which include same.

Description

The present invention relates to polymer mixtures containing aqueous liquid-absorbing hydrogel-forming polymers, produced by polymerizing olefinically unsaturated carboxylic acids or their derivatives, together with copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides, and to their preparation, use in hygiene articles and hygiene articles, that contain them. In particular, the invention relates to 2-component polymer mixtures of hydrogel-forming polymers with copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides.

Swellable hydrogel-forming polymers, so-called Superabsorbents (Super Absorbing Polymers) are from the prior art Technology known. These are networks more flexible hydrophilic polymers that are both ionic and can be non-ionic in nature. These are watery Absorb and absorb liquids to form a hydrogel bind and are therefore preferred for the production of Tampons, diapers, sanitary napkins, incontinence articles, Training underwear for children, shoe inserts and other hygiene items the absorption of body fluids. superabsorbent are also used in other areas of technology at which liquids, especially water or aqueous solutions be absorbed. These areas are e.g. B. storage, packaging, Transport (packaging material for water-sensitive articles such as Flower transport, shock protection); Food sector (Transport of fish, fresh meat; absorption of water, blood in fresh fish / meat packaging); Medicine (wound plaster, water-absorbent material for fire associations or for others oozing wounds), cosmetics (carrier material for pharmaceutical chemicals and medicines, rheumatic plasters, ultrasound gel, cooling gel, Cosmetic thickener, sun protection); Thickener for oil / water or Water / oil emulsions; Textile (gloves, sportswear, Moisture regulation in textiles, shoe inserts); chemical process industry. Applications (catalyst for organic reactions, immobilization of large functional molecules (enzymes), adhesive for agglomerations, Heat storage, filtration aids, hydrophilic component in Polymer laminates, dispersants, plasticizers); Construction and Construction, installation (powder injection molding, clay-based Plaster, anti-vibration medium, auxiliary materials Tunnel excavations in water-rich subsoil, cable sheathing); Water treatment, waste treatment, water separation (deicing agent, reusable sandbags); Cleaning; agribusiness (Irrigation, retention of melt water and dew precipitation, Composting additive, protection of forests against fungal / insect attack, delayed release of active substances on plants); in fire protection (Flying sparks) (covering houses or covering house walls with SAP gel, because the water has a very high heat capacity, ignition can be prevented; Spraying SAP Gel at Fires such as B. forest fires); Coextrusion in thermoplastic polymers (hydrophilization of Multilayer films); Manufacture of foils and thermoplastic Shaped bodies that can absorb water (e.g. rain and thaw water agricultural storage films; SAP-containing foils for Keeping fruits and vegetables fresh, packaged in moist films can be; SAP saves fruit and vegetables Water without the formation of condensation drops and gives the water partly on the fruit and vegetables again, so that neither rots withering still entered; SAP polystyrene coextrudates e.g. B. for Food packaging such as meat, fish, poultry, fruit and Vegetables); Carrier substance in active ingredient formulations (pharmaceuticals, Plant protection). The are in the hygiene articles Superabsorbers usually in the so-called absorbent core, which is another Materials include fibers (cellulose fibers) that as a kind of fluid reservoir that spontaneously acted upon Intermediately store liquid quantities and a good sewage system the body fluids in the absorbent core to the superabsorbent should guarantee.

The current trend in the hygiene sector, e.g. B. in diaper construction consists of thinner constructions with reduced To produce cellulose fiber and increased hydrogel content. With the trend that has become ever thinner diaper constructions Profile of requirements for water-swellable hydrophilic polymers changed significantly over the years. While at the beginning of the Development of highly absorbent hydrogels initially only the very high Swelling was in the foreground, it was later shown that also the ability of the superabsorbent to Fluid transfer and distribution is critical. It has it has been shown that conventional superabsorbents on the surface swell strongly when wetted with liquid, so that the Liquid transport into the interior of the particle is very difficult or completely is prevented. This peculiarity of the super absorber is also called Referred to as "gel blocking". Due to the higher loading of the Hygiene articles (polymer per unit area) the polymer may be in the swollen condition no junction for subsequent Form liquid. If the product has good transport properties, this allows optimal use of the entire hygiene article be guaranteed. The phenomenon of gel blocking is thus prevented, in extreme cases, to the escape of the liquid, the so-called leakage of the hygiene article leads. The Liquid transfer and distribution is thus at the initial absorption of vital body fluids.

A variety of work has attempted absorbing Generate structures that have no additions of Have cellulose fibers or other nonwoven fiber materials that in Ideally, even form continuous hydrogel zones by one higher load of the absorbent core with highly absorbent To ensure hydrogel-forming polymer material.

Use is also found in the literature water-absorbent films, which also hydrogel-forming Polymers are based, but their monomer solution before Polymerization is applied to the surface, or, starting from Hydrogel-forming polymer particles, an intramolecular Networking to macro structures is carried out. This is how JP 04004247 describes it the production of a water-absorbing film Maleic anhydride copolymer whose structural units are based on (I) alpha-olefinic or styrene units and (II) Maleic anhydride structures are based.

However, water-absorbing films are used Problems with fluid transport because of insufficient Diffusion times through the hydrogel Liquid transfer into the lower layers is made difficult or even prevented. The same applies when using hydrogel-forming polymer particles in high concentration, during which it swells to mutual contact of the swollen hydrogel particles comes, and so a gel-continuous zone is formed.

For example, hydrogels have good transport properties, which have a high gel strength when swollen. Gels with little gel strength are below one applied Pressure (body pressure) deformable, clog pores in the Superabsorbent / cellulose fiber absorbent body and thereby prevent one further fluid intake. Increased gel strength is in generally achieved through higher networking, whereby however, the retention of the product is reduced. Corresponding the nature of hydrogel-forming polymers, Properties such as high absorption capacity and high gel strength in to unite a product.

A way to increase gel strength while preserving Surface post-crosslinking provides high absorption capacities In this process, dried superabsorbents are used average network density of an additional Subject to networking. The process is known to the expert and z. B. in patent EP-A-0 349 240. Through the Post-crosslinking increases the crosslinking density in the shell of the Superabsorbent particles, causing absorption under pressure a higher level is raised. While the absorption capacity sinks in the super absorber shell, the core of the Superabsorbent particles due to the presence of mobile polymer chains an improved absorption capacity compared to the shell so that the shell structure improves Liquid transfer is guaranteed without the effect of Gel blocking occurs. It is entirely desirable that the Total capacity of the superabsorbent is not spontaneous, but is exhausted with a time lag. Because the hygiene article usually The urine must be absorbed several times of the superabsorbent does not make sense after the first Disposition to be exhausted. However, the problem remains insufficient acquisition times, especially in the areas of the hygiene item must be optimized in which most Liquid is applied.

If hydrogels are used in the hygiene sector, they will Body fluids such as urine or menstrual blood exposed. The body fluids generally contain unpleasant smelling Components of the amine or fatty acid type, which in addition to the already existing organic components (such as amines, Acids, alcohols, aldeydes, ketones, phenols, polycycles, indoles Aromatics, polyaromatics etc.), which are used for unpleasant body odors are responsible. The Odor development takes place in two stages: the first is at the outlet from the region of the body, and then when the fluid is already a is present in the absorption medium for a defined time. Both Odor factors need to be eliminated as it is for cost reasons is undesirable, the hygiene article after each absorption process switch.

For the use of the highly swellable hydrogels on the Hygiene sector are currently used polymers, which one Degree of neutralization between 60 and 80 mol%, based on the polymerized monomer units containing acid groups. During the odor control, however, it was found that in general a higher pH value favors bacterial growth. Doing so the urea in urine is increased by urease in carbon dioxide and Ammonia split, causing a further increase in pH leads. This in turn increases bacterial growth, and that Enzyme activity is further increased. As a result of the increased pH there is skin softening, which makes them more susceptible to Bacterial infestation. The immediate result of this is skin irritation, which exclude a longer wearing time of the hygiene article.

Odor control when using acidic hydrogels in Hygiene items are good. However, already show in Manufacturing processes according to the prior art disadvantages, because the Polymerization of the monomer solution proceeds very slowly, so that only a discontinuous procedure is possible. In addition, there are significant problems in breaking up the whole acidic polymer gel, and the neutralization afterwards is only controlled by diffusion, so that the Polymer surface has an excess of base.

• - Geruchskontrolle bei gleichzeitiger Absorption durch Zugabe inerter anorganischer Substanzen mit großer Oberfläche, in aller Regel als Feststoff auf die Oberfläche von Pulvern oder Granulaten zur Konfektionierung absorbierender Polymerer. Hier gelangen Zeolithe, Aktivkohle, Bentonite, feinteilige amorphe Polykieselsäuren (Silica) wie AEROSIL® oder CAB-O- SIL® zum Einsatz.
• - Zugabe von Substanzen, die unter Komplexbildung mit organischen Molekülen oder mit Metallionen, die in der Körperflüssigkeit vorliegen, reagieren, und die dadurch die Entwicklung unangenehmer Gerüche verhindern. Dies geschieht bevorzugt durch den Einsatz von Cyclodextrinen (jede Modifikation unsubstituierter Cyclodextrine, die 6 bis 12 Glucoseeinheiten enthält, wie beispielsweise alpha-Cyclodextrin, beta-Cyclodextrin, gamma-Cyclodextrin und/oder ihren Derivaten und/oder Mischungen daraus). Mischungen von Cyclodextrinen sind bevorzugt, da eine breitere Komplexierung organischer Moleküle über einen weiteren Molekulargewichtsbereich erfolgt. Cyclodextrine werden von 0.1% bis etwa 25%, bevorzugt von 1% bis etwa 20%, besonders bevorzugt von 2% bis etwa 15%, insbesondere bevorzugt von 3 bis 10%, bezogen auf das Gesamtgewicht der Zusammensetzung, eingesetzt. Cyclodextrine werden in kleiner Partikelgröße (meist kleiner als 12 µm) zugesetzt, um zur Geruchseliminierung eine große Oberfläche anzubieten. Weitere Komplexbildner: Aminopolycarbonsäuren und ihre Salze, Ethylendiamintetraacetat EDTA Ethylendiaminpentamethylenphosphonsäure, Ethylendiamintetramethylenphosphonsäure, Aminophosphate, polyfunktionelle Aromaten, N,N-Disuccinsäure.
• - Maskierung unangenehmer Gerüche durch Zusatz von Parfüms bzw. Deodorants. Diese werden in freier Form oder in eingekapselter Form (beispielsweise in Cyclodextrinen) zugesetzt. Letztere Form erlaubt es, das Parfüm zeitverzögert freizusetzen. Beispiele von Parfüms sind, ohne sich jedoch darauf zu beschränken: Allylcaproat, Allylcyclohexanacetat, Allylcyclohexanpropionat, Allylheptanoat, Amylacetat, Amylpropionat, Anetol, Anisol, Benzaldehyd, Benzylacetat, Benzylaceton, Benzylalkohol, Benzylbutyrat, Benzylformat, Benzylisovalerat, Benzylpropionat, Butylbenzoat, Butylcaproat, Campher, cis-3-Hexenylacetat, cis-3-Hexenylbutyrat, cis-3-Hexenylcaproat, cis-3-Hexenylvalerat, Zitronellol, Zitronellylderivate, Cyclal C, Cyclohexylethylacetat, 2-Decenal, Decylaldehyd, Dihydromyrcenol, Dimethylbenzylcarbinol und deren Derivate, Dimethyloktanol, Diphenyloxid, Ethylacetat, Ethylacetoacetat, Ethylamylketon, Ethylbenzoat, Ethylbutyrat, Ethylhexylketon, Ethylphenylacetat, Eucalyptol, Fenchylacetat, Fenchylalkohol, Tricyclodecenylacetat, Tricyclodecenylpropionat, Geraniol, Geranyl-Derivate, Heptylacetat, Heptylisobutyrat, Heptylpropionat, Hexenol, Hexenylacetat, Hexenylisobutyrat, Hexylacetat, Hexylformat, Hexylisobutyrat, Hexylisovalerat, Hexylneopentanoat, Hydroxycitronellal, α-Ionon, β-Ionon, γ-Ionon, Isoamylalkohol, Isobornylacetat, Isobornylpropionat, Isobutylbenzoat, Isobutylcaproat, Isononylacetat, Isononylalkohol, Isomenthol, Isomenthon, Isononylacetat, Isopulegol, Isopulegylacetat, Isoquinolin, Dodecanal, Lavandulylacetat, Ligustral, δ-Limonen, Linalool und Derivate, Menthon, Menthylacetat, Methylacetophenon, Methylamylketon, Methylanthranilat, Methylbenzoat, Methylbenzylacetat, Methylchavicol, Methyleugenol, Methylheptenon, Methylheptincarbonat, Methylheptylketon, Methylhexylketon, Methylnonylacetaldehyd, α-iso"γ"Methylionon, Methyloktylacetaldehyd, Methyloktylketon, Methylphenylcarbinylacetat, Methylsalicylat, Myrcen, Myrcenylacetat, Neral, Nerol, Nerylacetat, Nonalakton, Nonylbutyrat, Nonylalkohol, Nonylacetat, Nonylaldehyd, Oktalakton, Oktylacetat, Oktylalkohol, Oktylaldehyd, D-Limonen, p-Kresol, p-Kresylmethylether, p-Kymene, p-Isopropyl- p-Methylacetophenon, Phenethylanthranilat, Phenoxyethanol, Phenylacetaldehyd, Phenylethylacetat, Phenylethylalkohol, Phenylethyldimethylcarbinol, α-Pinen, β-Pinen, α-Terpinen, γ-Terpinen, Terpineol, Terpinylacetat, Terpinylpropionat, Tetrahydrolinalool, Tetrahydromyrcenol, Thymol, Prenylacetat, Propylbutyrat, Pulegon, Safrol, δ-Undecalakton, γ-Undecalakton, Undecanal, Undecylalkohol, Veratrol, Verdox, Vertenex, Viridin.
• - Zugabe von Ureaseinhibitoren, die die Bildung oder Aktivität von Enzymen unterbinden, die für die Spaltung von Harnstoff in Ammoniak und somit für die Geruchsentwicklung verantwortlich zeichnen.
• - Zugabe antimikrobieller Substanzen. Enzyme kontrollieren das bakterielle Wachstum und minimieren dadurch die Geruchsentwicklung, die über bakterielle Abbauvorgänge entsteht (z. B. Oxidoreductase + Mediator). Beispiele antimikrobieller Substanzen schließen quaternäre Ammoniumverbindungen, Phenole, Amide, Säuren und Nitroverbindungen, sowie deren Mischungen mit ein.

So far, the following options have been available for odor control in the hygiene sector:

• - Odor control with simultaneous absorption by adding inert inorganic substances with a large surface area, usually as a solid on the surface of powders or granules for the assembly of absorbent polymers. Zeolites, activated carbon, bentonites, fine-particle amorphous polysilicic acids (silica) such as AEROSIL® or CAB-O-SIL® are used here.
• - Addition of substances which react with the formation of complexes with organic molecules or with metal ions which are present in the body fluid, and which thereby prevent the development of unpleasant odors. This is preferably done by using cyclodextrins (any modification of unsubstituted cyclodextrins that contains 6 to 12 glucose units, such as alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin and / or their derivatives and / or mixtures thereof). Mixtures of cyclodextrins are preferred, since organic molecules are complexed over a wider molecular weight range. Cyclodextrins are used from 0.1% to about 25%, preferably from 1% to about 20%, particularly preferably from 2% to about 15%, particularly preferably from 3 to 10%, based on the total weight of the composition. Cyclodextrins are added in small particle sizes (usually smaller than 12 µm) in order to offer a large surface area for eliminating odors. Other complexing agents: aminopolycarboxylic acids and their salts, ethylenediaminetetraacetate EDTA ethylenediaminopentamethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, aminophosphates, polyfunctional aromatics, N, N-disuccinic acid.
• - Masking of unpleasant smells by adding perfumes or deodorants. These are added in free form or in encapsulated form (for example in cyclodextrins). The latter form allows the perfume to be released with a time delay. Examples of perfumes include, but are not limited to: allyl caproate, allyl cyclohexane acetate, allyl cyclohexane propionate, allyl heptanoate, amyl acetate, amyl propionate, anetol, anisole, benzaldehyde, benzyl acetate, benzylacetone, benzyl alcohol, benzyl butylate, benzyl formate, benzylate benzylate, benzyl formate cis-3-hexenylacetate, cis-3-hexenylbutyrate, cis-3-hexenylcaproate, cis-3-hexenylvalerate, citronellol, citronellyl derivatives, Cyclal C, cyclohexylethylacetate, 2-decenal, decylaldehyde, dihydromyrcenol, dimethylbenzyl derivative, dimethylbenzyl derivative, ethyl acetate, ethyl acetoacetate, ethyl amyl ketone, ethyl benzoate, ethyl butyrate, Ethylhexylketon, ethyl phenyl acetate, eucalyptol, fenchyl acetate, fenchyl alcohol, tricyclodecenyl acetate, tricyclodecenyl propionate, geraniol, geranyl derivatives, heptyl acetate, Heptylisobutyrat, Heptylpropionat, hexenol, hexenyl acetate, hexenyl isobutyrate, hexyl acetate, Hexylformat, Hexylisobutyrat, Hexylisovalerat , Hexylneopentanoate, hydroxycitronellal, α-ionon, β-ionon, γ-ionon, isoamyl alcohol, isobornylacetate, isobornylpropionate, isobutylbenzoate, isobutylcaproate, isononylacetate, isononyloethol, isoponuloetholate, isopulonoethololate, isopulonoethylacetate, isopulonoethylacetate, isoponyloetholate, isoponyloetholone -Limones, linalool and derivatives, menthone, menthyl acetate, methyl acetophenone, methyl amyl ketone, methyl anthranilate, methyl benzoate, methyl benzyl acetate, methyl chavicol, methyleugenol, methylheptenone, methylheptin carbonate, methylheptyl ketone, methyl hexyl ketone, methyl "nyllacetaldehyde" , Myrcene, myrcene acetate, neral, nerol, nerylacetate, nonalactone, nonyl butyrate, nonyl alcohol, nony acetate, nonyl aldehyde, octalactone, octylacetate, octyl alcohol, octyl aldehyde, D-limonene, p-cresol, p-cresyl methyl ether, p-kyopropyl, p-isopropyl, p-isopropyl -Methyl acetophenone, phenethylanthranilate, phenoxyethanol, Ph enylacetaldehyde, phenylethyl acetate, phenylethyl alcohol, phenylethyldimethylcarbinol, α-pinene, β-pinene, α-terpinene, γ-terpinene, terpineol, terpinylacetate, terpinylpropionate, tetrahydrolinalool, tetrahydromyrcenol, thymol, propyldonolate, prenonyl-trolonolate, prenonyl-prol-yl-oleol-prenyl-oleol-prenyl-oleol-prenyl-acetol-prenyl-oleol-prenyl-acetol-prenyl-ole-ol-prenyl-acyl-prenyl-oleol-prenyl-oleol-prenyl-acyl-prenyl-acyl-prenyl-acyl-prenonyl-olefin-prenyl-acyl-prenyl-acyl-prenyl-acyl-prenyl-acyl-prenyl-acyl-prenonyl-prenyl-olefin-prenyl-acyl-prenyl-oleol Undecalactone, Undecanal, Undecyl Alcohol, Veratrol, Verdox, Vertenex, Viridin.
• - Addition of urease inhibitors that prevent the formation or activity of enzymes that are responsible for the splitting of urea into ammonia and thus for the development of odors.
• - addition of antimicrobial substances. Enzymes control bacterial growth and thereby minimize the development of odors that arise through bacterial degradation processes (e.g. oxidoreductase + mediator). Examples of antimicrobial substances include quaternary ammonium compounds, phenols, amides, acids and nitro compounds, and mixtures thereof.

Examples of quaternary ammonium compounds include 2- (3-anilinovinylul) 3,4-dimethyloxazoliniumiodid, Alkylisoquinolium bromide, benzalkonium chloride, benzethonium chloride, Cetylpyridinium chloride, chlorhexidine gluconate, chlorhexidine hydrochloride, Lauryltrimethylammonium compounds, methylbenzethonium chloride, Stearyltrimethylammonium chloride, 2,4,5-trichlorophenoxide, and their Mixtures with one.

Examples of phenols include benzyl alcohol, p-chlorophenol, Chlorocresol, chloroxylenol, cresol, o-kymene-5-ol (BIOSOL), Hexachlorophene, quinokitiol, isopropylmethylphenol, parabens (with Methyl, ethyl, propyl, butyl, isobutyl, isopropyl, and / or Sodium methyl substituents), phenethyl alcohol, phenol, Phenoxyethanol, o-phenylphenol, resorcinol, resorcinol monoacetate, Sodium parabens, sodium phenolsulfonate, thioxolone, 2,4,4'-trichloro-2'-hydroxidiphenyl ether, zinc phenol sulfonate, di-tert-butylphenol, Hydroquinone; BHT, as well as their mixtures.

Examples of amides include diazolidinyl urea, 2,4-imidazolidinedi-one (HYDATOIN), 3,4,4'-trichlorocarbonilide, 3-trifluoromethyl-4,4'-dichlorocarbonilide, undecylenic acid monoethanolamide, as well as their mixtures.

Examples of acids include benzoates, benzoic acid, Citric acid, dehydroacetic acid, potassium sorbate, sodium citrate, Sodium dehydroacetate, sodium salicylate, sodium salicylic acid, Sorbitan acid, undecylenic acid, zinc undecylenate, zinc oxide, Zinc phenol sulfonate, ascorbic acid, acetylsalicylic acid, salicylaldehyde, Salicylic acid derivatives, adipic acid, adipic acid derivatives, and their mixtures with a.

Close examples of nitro compounds 2-bromo-2-nitro-2,3-propanediol (BRONOPOL), Methyldibromoglutaronitrile and Propyuleneglycol (MERGUARD), as well as their mixtures with a.

• - Einsatz von Übergangsmetallverbindungen (Cu, Ag, Zn).
• - Einsatz von Mikrokapseln, welche die Aktivsubstanz bei Feuchtigkeit freisetzen;

In addition, the following compounds are also suitable as biocides: 2,5-dimethoxytetrahydrofuran, 2,5-diethoxytetrahydrofuran, 2,5-dimethoxy-2,5-dihydrofuran, 2,5-diethoxy-2,5-dihydrofuran, succinic dialdehyde, glutardialdehyde, Glyoxal, glyoxylic acid, hexahydrotriazine, tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione (Dazomet), 2,4-dichlorobenzyl alcohol, benzalkonium chloride, chlorhexidine gluconate, triclosan.

• - Use of transition metal compounds (Cu, Ag, Zn).
• - Use of microcapsules, which release the active substance when damp;

In addition to the designated connection classes, the Odor control the following compounds are also used: peroxides, Hydrogen carbonate, triclosan, plant extracts, essential oils, Boron compounds, poly-alpha-amino acids, (polylysine), imides, Polyimides, PVP iodine, use of certain polymeric substances such as chitosan, polyglycosides, oxidizing agents, cyclophanes.

In general, however, the addition of an odor-inhibiting effect Substances adversely affect the absorption profile of the highly swellable Hydrogels. Therefore, the invention Polymer mixtures preferably without these anti-fouling substances used.

The task now was to create a product with the objective develop, with high absorption performance and / or Swelling speed at the same time has odor-binding properties.

It has surprisingly been found that good odor control can be achieved by adding copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides to conventional hydrogel-forming polymers.

The present invention accordingly relates to polymer mixtures comprising aqueous liquid-absorbing hydrogel-forming polymers, produced by polymerizing olefinically unsaturated carboxylic acids or their derivatives (component (i)), with copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides (components (ii) ). The polymer mixtures according to the invention preferably relate to granular or fibrous aqueous liquid-absorbing hydrogel-forming polymers, produced by polymerizing olefinically unsaturated carboxylic acids or their derivatives, in combination with granular or fibrous copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides. Alternatively, the copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides can also be sprayed onto hydrogel-forming polymers which absorb granular or fibrous aqueous liquids and are prepared by polymerizing olefinically unsaturated carboxylic acids or their derivatives. In the present invention, granular or fibrous hydrogel-forming polymers absorbing aqueous liquids, produced by polymerizing olefinically unsaturated carboxylic acids or their derivatives, are not understood to mean copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides. Preference is given to the aqueous liquid-absorbing hydrogel-forming polymers produced by polymerizing acrylic acid or its salts. These aqueous liquid-absorbing hydrogel-forming polymers are therefore preferably based on polyacrylate. The copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides can themselves be hydrogel-forming, e.g. B. in which they are partially saponified. Here, 15 mol% or less is preferably partially saponified. Unsaponified copolymers are particularly preferred. Polymer mixtures are preferably produced by a process in which the hydrogel-forming polymer and the copolymer of C ₂ -C ₈ olefins or styrenes are prepared with anhydrides in two process steps and then mixed in a defined ratio.

The copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides are preferably used unsaponified in powder form (granular). If this copolymer is used in the hygiene sector, the basic components formed by enzymatic processes or bacterial degradation reactions, e.g. B. ammonia, which are essentially responsible for the development of odors. According to the invention, the anhydride component is preferably understood to mean anhydrides of olefinically unsaturated di- or polycarboxylic acids, e.g. B. by one or two C ₁ -C ₆ alkyl groups substituted maleic acid. Di-carboxylic acids are preferred. Maleic anhydride is particularly preferred. The C ₂ -C ₈ olefins are understood to mean unsaturated compounds which contain 2 to 8 C atoms. Optionally, 1 or more heteroatoms such as O, N, S can also be included. For example, the following monomers are understood as ethylene, propylene, isobutylene, 1-butylene, C ₁ -C ₄ methacrylates, vinyl acetate, methyl vinyl ether, isobutyl vinyl ether, 1-hexene. The monomers can be pure or in mixtures. Isobutylene and vinyl acetate are preferred. Styrenes are understood to mean styrene and substituted styrenes. At the alpha carbon z. B. a C ₁ -C ₆ alkyl group and / or the benzene ring can be substituted with one or more C ₁ -C ₆ alkyl groups and / or one or more hydroxy groups. Styrene is preferred. In general, the molar ratio between anhydride and olefin or styrene is between 3 to 1 and 1 to 3, preferably between 2.5 to 1 and 1 to 2.5, particularly preferably between 2 to 1 and 1 to 2, in particular 1 to 1. If there is an excess of one component, an anhydride excess is preferred. The copolymers with maleic anhydride and isobutylene, diisobutylene, ethylene or styrene, all optionally with the addition of vinyl acetate, are particularly preferred.

Surprisingly, it has also been found that by adding granular or fibrous copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides to the hydrogel-forming polymers from the prior art, the permeability can be largely increased.

The aqueous liquid-absorbing hydrogel-forming polymers can also be mixed with monomer solution or polymer solution of C ₂ -C ₈ olefins or styrenes with anhydrides. Inert solvents such as acetone, DMSO, dioxane, ethyl acetate, chloroform or toluene are suitable as solvents. The monomer or polymer solutions can be sprayed onto the hydrogels and optionally subjected to precipitation polymerization. The solvent is expediently removed by drying at 20 to 120 ° C.

The molecular weights of the copolymers are generally between 500 and 1 million, preferably between 1000 and 250,000.

The proportion of hydrogel-forming polymer particles has a high absorption capacity with good swelling rate, while the retention of the anhydride units buffering the proportion of basic components, e.g. B. the ammonia portion guaranteed. By adding copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides, an improved permeability can also be achieved.

In a preferred embodiment of the present invention, copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides which are in the form of fibers are added to the hydrogel-forming polymers. To enable spinning, the copolymer of C ₂ -C ₈ olefins or styrenes is partially saponified with anhydrides. Such partially neutralized copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides are described, for example, in US Pat. No. 5,026,784. An aqueous copolymer solution suitable for spinning is then obtained from (column 3, line 6) a) partially neutralized C ₂ -C ₈ olefin / anhydride, in particular maleic anhydride copolymer with a degree of neutralization of 0.2 to about 0.8 equivalents of carboxyl group units with b) 0.1 up to 10 parts by weight of at least one reactive component based on 100 parts by weight of partially neutralized polymer dissolved in aqueous liquid. The reactive component is a water-soluble component which has an amino group and at least one hydroxyl group. The reaction product has an ionic ammonium carboxylate bond, which is formed by unneutralized carboxyl groups of the polymer and the amino group of the reactive substance.

After spinning, the fibers are heated to 140 to 210 ° C, a crosslinking takes place under water leakage, in which Ester and amide bonds are formed. The so networked Fibers are water-swellable and therefore absorbent.

The addition of partially neutralized copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides in fiber form can enable higher acquisition rates and higher retention values than is the case with the granular polymer mixture according to the invention. Anhydride groups are consumed in the partial saponification, so either more copolymer fractions are generally used and / or known odor inhibitors are added. The degree of terile saponification is preferably at or below 15 mol%.

A particularly preferred embodiment of the present invention accordingly relates to polymer mixtures comprising aqueous liquid-absorbing hydrogel-forming polymers, produced by polymerizing olefinically unsaturated carboxylic acids or their derivatives, with copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides (granular or by spraying) , and partially saponified C ₂ -C ₈ olefin / anhydride, especially maleic anhydride copolymer fibers.

Polymer mixtures can be mixtures of hydrogel-forming polymers which absorb dry aqueous liquids and can be produced by polymerizing olefinically unsaturated carboxylic acids or their derivatives with dry granular copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides. The former can also have a residual water content that is lower than their respective CRC. The residual moisture content is preferably less than the weight of the superabsorbent, more preferably less than 30% by weight of residual moisture, in particular less than 10% by weight of residual moisture. Olefinically unsaturated carboxylic acids are preferably understood to mean monoethylenically unsaturated monomers. Among their derivatives, salts, esters, e.g. B. C ₁ -C ₆ alkyl esters, anhydrides, etc. understood, which can be hydrolyzed to the free acids.

Preferred polymer mixtures are characterized in that they are powder mixtures of hydrogel-forming polymers which absorb aqueous liquids (component (i)) with copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides (component (ii)).

Polymer mixtures are also preferred characterized in that the component (i) to 99.7 wt% to 85 wt% and component (ii) is present in 0.3% by weight to 15% by weight, in particular those in which the component (ii) up to 0.5% by weight 10% by weight is present, d. H. z. B. to 9, 8, 7, 6, 5, 4, 3, 2, 1, or Intermediate weight percentages. The further or further Components then each give 100% by weight.

In a particularly preferred embodiment of the present invention, component (ii) is a mixture of granular C ₂ -C ₈ olefin / anhydride, in particular maleic anhydride copolymer and aqueous liquid-absorbing C ₂ olefin / anhydride, in particular maleic anhydride copolymer - fibers.

Also preferred are polymer mixtures, characterized in that granular C ₂ -C ₈ olefin / anhydride, in particular maleic anhydride copolymer (A) and aqueous liquid-absorbing C ₂ -C ₈ olefin / anhydride, in particular maleic anhydride copolymer fiber (B) than the two components of component (ii), 50% by weight to 90% by weight of component (A) and 10% by weight to 50% by weight of component (B) or intermediate weight percentages. The further or further components then together with the two main components each result in 100% by weight.

The polymer mixtures mentioned may vary depending on the application characterized in that the components of the mixture Particles of the same or different grain size getting produced. Those of the same grain size fraction are preferred.

The individual components are according to the optional Surface post-crosslinking of component (i) mixed.

In addition, various applications for the Polymer mixtures as absorbents for aqueous liquids, Dispersions and emulsions disclosed, especially various Hygiene article constructions containing the above polymer mixtures. The use of the invention according to is particularly preferred Polymer mixtures as absorbents for aqueous Liquids with reduced odor. decreased Odor formation means that adding 10% by weight of the copolymers the buffer capacity by at least 0.2 pH units, preferably at least 0.5 pH units, particularly preferably at least 0.7 pH units, especially at least 1.0 pH units is improved.

Manufacturing process Hydrogel-forming polymers

The production of the water-swellable hydrophilic Hydrogel-forming polymers are usually made by free radicals Polymerization in aqueous solution that the monomers, as well optionally contains graft base and crosslinker.

Monomers used

Hydrogel-forming polymers are, in particular, polymers made from (Co) polymerized hydrophilic monomers, graft (co) polymers from one or more hydrophilic monomers to a suitable one Graft base, cross-linked cellulose or starch ether, cross-linked Carboxymethyl cellulose, partially cross-linked polyalkylene oxide or natural products swellable in aqueous liquids, such as for example guar derivatives, alginates and carrageenans.

Suitable graft bases can be of natural or synthetic origin. Examples are starch, cellulose or cellulose derivatives, such as. B. carboxymethyl cellulose, and other polysaccharides and oligosaccharides, polyvinyl alcohol, polyalkylene oxides, especially polyethylene oxides and polypropylene oxides, polyamines, polyamides and hydrophilic polyesters. Suitable polyalkylene oxides have, for example, the formula R ¹ -O- (CH ₂ -CHX-O-) _n R ²
R ¹ and R ² independently of one another are hydrogen, alkyl, alkenyl or aryl,
X is hydrogen or methyl and
n is an integer from 1 to 10,000.

R ¹ and R ^{2 are} preferably hydrogen, (C ₁ -C ₄ ) alkyl, (C ₂ - C ₆ ) alkenyl or phenyl.

Crosslinked polymers are preferred as hydrogel-forming polymers with acid groups, mainly in the form of their salts, in the Usually alkali or ammonium salts are present. Such polymers swell particularly strongly on contact with aqueous liquids to gel on.

Polymers produced by crosslinking polymerization are preferred or copolymerization of acid-bearing monoethylenic unsaturated monomers or their derivatives, e.g. B. salts, esters, Anhydrides can be obtained. It is also possible to use these monomers to (co-) polymerize without crosslinker and subsequently to network.

Monomers bearing such acid groups are, for example, monoethylenically unsaturated C ₃ -C ₂₅ -carboxylic acids or anhydrides such as acrylic acid, methacrylic acid, ethacrylic acid, α-chloroacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid and fumaric acid. Also suitable are monoethylenically unsaturated sulfonic or phosphonic acids, for example vinylsulfonic acid, allylsulfonic acid, sulfoethyl acrylate, sulfomethacrylate, sulfopropyl acrylate, sulfopropyl methacrylate, 2-hydroxy-3-acryloxypropylsulfonic acid, 2-hydroxy-3-methacryloxypropylsulfonic acid, stylphosphonic acid, allylphosphonic acid, allylphosphonic acid, allylphosphonic acid, acrylamido-2-methyl propane sulfonic acid. The monomers can be used alone or as a mixture with one another.

Monomers used with preference are acrylic acid, methacrylic acid, Vinylsulfonic acid, acrylamidopropanesulfonic acid or mixtures these acids, e.g. B. mixtures of acrylic acid and Methacrylic acid, mixtures of acrylic acid and acrylamidopropanesulfonic acid or mixtures of acrylic acid and vinyl sulfonic acid.

To optimize properties, it can be useful to use additional monoethylenically unsaturated compounds which do not carry any acid groups, but which can be copolymerized with the monomers bearing acid groups. These include, for example, the amides and nitriles of monoethylenically unsaturated carboxylic acids, e.g. As acrylamide, methacrylamide and N-vinylformamide, N-vinyl acetamide, N-methyl-vinyl acetamide, acrylonitrile and methacrylonitrile. Other suitable compounds are, for example, vinyl esters of saturated C ₁ - to C ₄ -carboxylic acids such as vinyl formate, vinyl acetate or vinyl propionate, alkyl vinyl ethers with at least 2 C atoms in the alkyl group, such as, for. B. ethyl vinyl ether or butyl vinyl ether, esters of monoethylenically unsaturated C ₃ - to C ₆ -carboxylic acids, for. B. esters of monohydric C ₁ - to C ₁₈ alcohols and acrylic acid, methacrylic acid or maleic acid, half-esters of maleic acid, for. B. maleic acid mono-methyl ester, N-vinyl lactams such as N-vinyl pyrrolidone or N-vinyl caprolactam, acrylic acid and methacrylic acid esters of alkoxylated monohydric, saturated alcohols, e.g. B. of alcohols with 10 to 25 carbon atoms which have been reacted with 2 to 200 moles of ethylene oxide and / or propylene oxide per mole of alcohol, and monoacrylic acid esters and monomethacrylic acid esters of polyethylene glycol or polypropylene glycol, the molar masses (M _n ) of the polyalkylene glycols, for example, up to can be up to 2000. Other suitable monomers are styrene and alkyl-substituted styrenes such as ethylstyrene or tert-butylstyrene.

These monomers which do not contain acid groups can also be used in Mixture with other monomers are used, for. B. Mixtures of vinyl acetate and 2-hydroxyethyl acrylate in any ratio. These monomers bearing no acid groups the reaction mixture in amounts between 0 and 50 wt .-%, preferably less than 20 wt .-% added.

Crosslinked polymers bearing acid groups are preferred monoethylenically unsaturated monomers, which may or may not be present or after the polymerization into their alkali or ammonium salts be transferred, and from 0-40 wt .-% based on it Total weight no acid-bearing monoethylenically unsaturated Monomers.

Crosslinked polymers of monoethylenically unsaturated C ₃ to C ₁₂ carboxylic acids and / or their alkali metal or ammonium salts are preferred. In particular, crosslinked polyacrylic acids are preferred whose acid groups are 5 to 30 mol%, preferably 5 to 20 mol%, particularly preferably 5 to 10 mol%, based on the monomers containing acid groups, as alkali or ammonium salts.

Compounds which have at least two can function as crosslinkers have ethylenically unsaturated double bonds. examples for Compounds of this type are N, N'-methylenebisacrylamide, Polyethylene glycol diacrylates and polyethylene glycol dimethacrylates, the each of polyethylene glycols with a molecular weight of 106 to 8500, preferably 400 to 2000, Trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate (ETMPTA) in particular ETMPTA, which ethoxylates with 15 EO on average is, trimethylolpropane trimethacrylate, ethylene glycol diacrylate, Ethylene glycol dimethacrylate, propylene glycol diacrylate Propylene glycol dimethacrylate, butanediol diacrylate, butanediol dimethacrylate, Hexanediol diacrylate, hexanediol dimethacrylate, allyl methacrylate, Diacrylates and dimethacrylates from block copolymers Ethylene oxide and propylene oxide, twice or more with Acrylic acid or methacrylic acid esterified polyhydric alcohols, such as Glycerin or pentaerythritol, triallylamine, Dialkyldiallylammonium halides such as dimethyldiallylammonium chloride and Diethyldiallylammonium chloride, tetraallylethylenediamine, divinylbenzene, Diallyl phthalate, polyethylene glycol divinyl ether from Polyethylene glycols with a molecular weight of 106 to 4000, Trimethylolpropane diallyl ether, butanediol divinyl ether, Pentaerythritol triallyl ether, reaction products of 1 mole of ethylene glycol diglycidyl ether or polyethylene glycol diglycidyl ether with 2 moles Pentaerythritol triallyl ether or allyl alcohol, and / or Divinylethylenharnstoff. Preferably, water-soluble crosslinking agents are used, e.g. B. N, N'-methylenebisacrylamide, polyethylene glycol diacrylates and Polyethylene glycol dimethacrylate, which differs from addition products 2 to 400 moles of ethylene oxide to 1 mole of a diol or polyol derive vinyl ethers from addition products from 2 to 400 mol Ethylene oxide on 1 mole of a diol or polyol, Ethylene glycol diacrylate, ethylene glycol dimethacrylate or triacrylates and Trimethacrylates of addition products of 6 to 20 moles of ethylene oxide 1 mole of glycerol, pentaerythritol triallyl ether and / or Divinylurea.

Also suitable as crosslinkers are compounds which at least one polymerizable ethylenically unsaturated group and contain at least one further functional group. The functional group of these crosslinkers must be able to use the functional groups, essentially the acid groups, the React monomers. Suitable functional groups are for example hydroxyl, amino, epoxy and aziridino groups. Can be used for. B. Hydroxyalkyl esters of the above mentioned monoethylenically unsaturated carboxylic acids, for. B. 2-hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, Hydroxyethyl methacrylate, hydroxypropyl methacrylate and Hydroxybutyl methacrylate, allyl piperidinium bromide, N-vinylimidazoles such as. B. N- Vinylimidazole, 1-vinyl-2-methylimidazole and N-vinylimidazolines such as N-vinylimidazoline, 1-vinyl-2-methylimidazoline, 1-vinyl-2-ethylimidazoline or 1-vinyl-2-propylimidazoline, which in Form of free bases, in quaternized form or as a salt the polymerization can be used. They are also suitable Dialkylaminoethyl acrylate, dimethylaminoethyl methacrylate, Diethylaminoethyl acrylate and diethylaminoethyl methacrylate. The basic ones Esters are preferably in quaternized form or as a salt used. Furthermore, e.g. B. also glycidyl (meth) acrylate be used.

Also suitable as crosslinkers are compounds which contain at least two functional groups that are capable are, with the functional groups, essentially the To react acid groups of the monomers. The suitable ones functional groups have already been mentioned above, i. H. hydroxyl, Amino, epoxy, isocyanate, ester, amido and aziridino groups. Examples of such crosslinkers are ethylene glycol, Diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, Glycerin, polyglycerin, triethanolamine, propylene glycol, Polypropylene glycol, block copolymers of ethylene oxide and Propylene oxide, ethanolamine, sorbitan fatty acid esters, ethoxylated Sorbitan fatty acid esters, trimethylolpropane, pentaerythritol, 1,3-butanediol, 1,4-butanediol, polyvinyl alcohol, sorbitol, starch, Polyglycidyl ethers such as ethylene glycol diglycidyl ether, Polyethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol polyglycidyl ether, Diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, Sorbitol polyglycidyl ether, pentaerythritol polyglycidyl ether, Propylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether, Polyaziridine compounds such as 2,2-Bishydroxymethylbutanoltris [3- (1-aziridinyl) propionate], 1,6-hexamethylene diethylene urea, diphenylmethane-bis-4,4'-N, N'-diethylene urea, Haloepoxy compounds such as epichlorohydrin and? -Methylpifluorohydrin, Polyisocyanates such as 2,4-tolylene diisocyanate and Hexamethylene diisocyanate, alkylene carbonates such as 1,3-dioxolan-2-one and 4-methyl-1,3-dioxolan-2-one, further bisoxazolines and Oxazolidones, polyamidoamines and their reaction products with Epichlorohydrin, also polyquaternary amines such as condensation products of Dimethylamine with epichlorohydrin, homo- and copolymers of Diallyldimethylammonium chloride and homo- and copolymers of Dimethylaminoethyl (meth) acrylate, optionally with for example, methyl chloride are quaternized.

Other suitable crosslinkers are polyvalent metal ions, which in are able to develop ionic networks. examples for such crosslinkers are magnesium, calcium, barium and Aluminum ions. These crosslinkers are, for example, as Hydroxides, carbonates or hydrogen carbonates are used. Further suitable crosslinkers are multifunctional bases, which are also in are able to form ionic networks, for example Polyamines or their quaternized salts. Examples of polyamines are ethylenediamine, diethylenetriamine, triethylenetetramine, Tetraethylene pentamine, pentaethylene hexamine and polyethyleneimines as well Polyamines with molecular weights of up to 4,000,000 each.

The crosslinkers in the reaction mixture are, for example, from 0.001 to 20 and preferably from 0.01 to 14 wt .-% based on Monomer present.

Radical polymerization

The polymerization is carried out as usual by a Initiator triggered. Also initiation of the polymerization by Action of electron beams on the polymerizable, aqueous mixture is possible. The polymerization can, however even in the absence of initiators of the type mentioned above Exposure to high energy radiation in the presence of Photoinitiators are triggered. As polymerization initiators can all radicalize under the polymerization conditions disintegrating compounds are used, e.g. B. peroxides, Hydroperoxides, hydrogen peroxides, persulfates, azo compounds and the so-called redox catalysts. Use is preferred of water-soluble initiators. In some cases it is advantageous to mixtures of different polymerization initiators use, e.g. B. Mixtures of hydrogen peroxide and sodium or potassium peroxodisulfate. Mixtures of hydrogen peroxide and Sodium peroxodisulfate can be in any ratio be used. Suitable organic peroxides are for example acetylacetone peroxide, methyl ethyl ketone peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, tert-amyl perpivalate, tert-butyl perpivalate, tert-butyl perneohexanoate, tert-butyl perisobutyrate, tert-butyl per-2-ethylhexanoate, tert-butyl perisononanoate, tert-butyl permaleate, tert-butyl perbenzoate, Di (2-ethylhexyl) peroxidicarbonate, dicyclohexylperoxidicarbonate, Di- (4-tert-butylcyclohexyl) peroxidicarbonate, dimyristilperoxidicarbonate, Diacetyl peroxidicarbonate, allyl perester, cumyl peroxyneodecanoate, tert-butyl per-3,5,5-trimethylhexanoate, Acetylcyclohexylsulfonyl peroxide, dilauryl peroxide, dibenzoyl peroxide and tert-Amylperneodekanoat. Particularly suitable polymerization initiators are water-soluble azo starters, e.g. B. 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (N, N'-dimethylene) isobutyramidine dihydrochloride, 2- (carbamoylazo) isobutyronitrile, 2,2'-azo- bis [2- (2'-imidazolin-2-yl) propane] dihydrochloride and 4,4'-azo bis- (4-cyanovaleric acid). The above Polymerization initiators are used in conventional amounts, e.g. B. in amounts of 0.01 to 5, preferably 0.05 to 2.0 wt .-%, based on the polymerizing monomers.

Redox catalysts are also suitable as initiators. The redox catalysts contain at least one of the above-mentioned per compounds as the oxidizing component and as reducing component, for example, ascorbic acid, glucose, sorbose, ammonium or alkali metal hydrogen sulfite, sulfite, thiosulfate, hyposulfite, pyro sulfite or sulfide, metal salts, such as iron ( II) ions or sodium hydroxymethyl sulfoxylate. Ascorbic acid or sodium sulfite is preferably used as the reducing component of the redox catalyst. Based on the amount of monomers used in the polymerization, 3 × 10 ^-6 to 1 mol% of the reducing component of the redox catalyst system and 0.001 to 5.0 mol% of the oxidizing component of the redox catalyst are used, for example.

If the polymerisation by exposure to high energy Radiation is usually used as an initiator so-called photoinitiators. This can be, for example so-called α-splitters, H-abstracting systems or azides act. Examples of such initiators are Benzophenone derivatives such as Michlers ketone, phenanthrene derivatives, fluorene derivatives, Anthraquinone derivatives, thioxanone derivatives, coumarin derivatives, Benzoin ethers and their derivatives, azo compounds such as those above radical generator, substituted hexaarylbisimidazoles or Acylphosphine. Examples of azides are: 2- (N, N-dimethylamino) ethyl-4-azidocinnamate, 2- (N, N-dimethylamino) ethyl 4-azidonaphthyl ketone, 2- (N, N-dimethylamino) ethyl 4-azidobenzoate, 5-azido-1-naphthyl-2 '- (N, N-dimethylamino) ethyl sulfone, N- (4-sulfonyl azidophenyl) maleimide, N-acetyl-4-sulfonyl azidoaniline, 4-sulfonylazidoaniline, 4-azidoaniline, 4-azidophenacyl bromide, p-azidobenzoic acid, 2,6-bis (p-azidobenzylidene) cyclohexanone and 2,6-bis (p-azidobenzylidene) -4-methylcyclohexanone. The If they are used, photoinitiators are usually used in Amounts of 0.01 to 5 wt .-% based on those to be polymerized Monomers applied.

The crosslinked polymers are preferably partially neutralized used. The degree of neutralization is preferably 5 to 60 mol%, preferably 10 to 40 mol%, particularly preferably 20 to 30 mol%, based on the monomers containing acid groups. As Neutralizing agents are possible: alkali metal bases or Ammonia or amines. Sodium hydroxide solution, potassium hydroxide solution or Lithium hydroxide used. However, neutralization can also with the help of sodium carbonate, sodium hydrogen carbonate, Potassium carbonate or potassium hydrogen carbonate or other carbonates or Hydrogen carbonates or ammonia can be made. In addition, prim., Sec. and tert. Amines can be used.

Alternatively, the degree of neutralization can be set during or after the polymerization in all suitable Apparatus can be made. The neutralization can for example when using a kneader for polymerization can also be made directly here. The different Degree of neutralization causes different pH values of the polymers.

As a technical process for the manufacture of these products all processes are used, which are usually used in the Production of superabsorbents are used, such as. B. in Chapter 3 in "Modern Superabsorbent Polymer Technology", F.L. Buchholz and A. T. Graham, Wiley-VCH, 1998.

Polymerization in aqueous solution is preferred as so-called gel polymerization. 10 to 70% by weight aqueous solutions of the monomers and, if appropriate, a suitable one Graft base in the presence of a radical initiator Utilization of the Trommsdorff-Norrish effect polymerized.

The polymerization reaction can take place in the temperature range between 0 ° C and 150 ° C, preferably between 10 ° C and 100 ° C, both at Normal pressure as well as under increased or reduced pressure be performed. As usual, the polymerization can also be carried out in a protective gas atmosphere, preferably under nitrogen, be carried out.

By reheating the polymer gels for several hours in the Temperature range 50 to 130 ° C, preferably 70 to 100 ° C, can Quality properties of the polymers can still be improved.

surface post

Hydrogel-forming polymers are preferred post-crosslinked. The surface post-crosslinking can in itself known way with dried, ground and sieved Polymer particles happen.

For this purpose, compounds with the functional groups of the Polymers can react with crosslinking, preferably in the form a water-based solution on the surface of the Hydrogel particles applied. The water-based solution can be water-miscible contain organic solvents. Suitable solvents are Alcohols such as methanol, ethanol, i-propanol, ethylene glycol, Propylene glycol or acetone.

In the subsequent crosslinking, polymers are formed by the Polymerization of the above monoethylenically unsaturated Acids and optionally monoethylenically unsaturated Comonomers were produced and which have a molecular weight greater than 5000, preferably have greater than 50,000, reacted with compounds which at least two groups reactive towards acid groups exhibit. This reaction can take place at room temperature or at elevated temperatures up to 220 ° C.

• - Di- oder Polyglycidylverbindungen wie Phosphonsäurediglycidylether oder Ethylenglykoldiglycidylether, Bischlorhydrinether von Polyalkylenglykolen,
• - Alkoxysilylverbindungen,
• - Polyaziridine, Aziridin-Einheiten enthaltende Verbindungen auf Basis von Polyethern oder substituierten Kohlenwasserstoffen, beispielsweise Bis-N-aziridinomethan,
• - Polyamine oder Polyamidoamine sowie deren Umsetzungsprodukte mit Epichlorhydrin,
• - Polyole wie Ethylenglykol, 1,2-Propandiol, 1,4-Butandiol, Glycerin, Methyltriglykol, Polyethylenglykole mit einem mittleren Molekulargewicht M_w von 200-10000, Di- und Polyglycerin, Pentaerythrit, Sorbit, die Oxethylate dieser Polyole sowie deren Ester mit Carbonsäuren oder der Kohlensäure wie Ethylencarbonat oder Propylencarbonat,
• - Kohlensäurederivate wie Harnstoff, Thioharnstoff, Guanidin, Dicyandiamid, 2-Oxazolidinon und dessen Derivate, Bisoxazolin, Polyoxazoline, Di- und Polyisocyanate,
• - Di- und Poly-N-methylolverbindungen wie beispielsweise Methylenbis(N-methylol-methacrylamid) oder Melamin-Formaldehyd-Harze,
• - Verbindungen mit zwei oder mehr blockierten Isocyanat-Gruppen wie beispielsweise Trimethylhexamethylendiisocyanat blockiert mit 2,2,3,6-Tetramethyl-piperidinon-4.

Suitable post-crosslinking agents are, for example

• Di- or polyglycidyl compounds such as phosphonic acid diglycidyl ether or ethylene glycol diglycidyl ether, bischlorohydrin ether of polyalkylene glycols,
• - alkoxysilyl compounds,
• Polyaziridines, compounds containing aziridine units based on polyethers or substituted hydrocarbons, for example bis-N-aziridinomethane,
• Polyamines or polyamidoamines and their reaction products with epichlorohydrin,
• - Polyols such as ethylene glycol, 1,2-propanediol, 1,4-butanediol, glycerol, methyltriglycol, polyethylene glycols with an average molecular weight M _w of 200-10000, di- and polyglycerol, pentaerythritol, sorbitol, the oxyethylates of these polyols and their esters with Carboxylic acids or carbonic acid such as ethylene carbonate or propylene carbonate,
• Carbonic acid derivatives such as urea, thiourea, guanidine, dicyandiamide, 2-oxazolidinone and its derivatives, bisoxazoline, polyoxazolines, di- and polyisocyanates,
• Di- and poly-N-methylol compounds such as methylenebis (N-methylol-methacrylamide) or melamine-formaldehyde resins,
• - Compounds with two or more blocked isocyanate groups such as trimethylhexamethylene diisocyanate blocked with 2,2,3,6-tetramethyl-piperidinone-4.

If necessary, acidic catalysts such as p-toluenesulfonic acid, phosphoric acid, boric acid or Ammonium dihydrogen phosphate can be added.

Particularly suitable post-crosslinking agents are di- or Polyglycidyl compounds such as ethylene glycol diglycidyl ether, the Reaction products of polyamidoamines with epichlorohydrin and 2-oxazolidinone.

The crosslinking agent solution is applied to the fine grain preferably by spraying a solution of the crosslinker in conventional reaction mixers or mixing and drying systems such as Patterson-Kelly mixers, DRAIS turbulence mixer, Lödige mixer, screw mixer, plate mixer, Fluid bed mixer and Schugi mix. After spraying the Crosslinking agent solution can follow a temperature treatment step, preferably in a downstream dryer, at a temperature between 80 and 230 ° C, preferably 80-190 ° C, and particularly preferred between 100 and 160 ° C, over a period of 5 minutes to 6 Hours, preferably 10 minutes to 2 hours and especially preferably 10 minutes to 1 hour, both fission products and Solvent components can be removed. The drying can but also in the mixer itself, by heating the jacket or blowing in a preheated carrier gas.

In a particularly preferred embodiment of the invention, the hydrophilicity of the particle surface of the hydrogel-forming polymers is additionally modified by the formation of complexes. The complexes are formed on the outer shell of the hydrogel particles by spraying on solutions of di- or polyvalent metal salt solutions, the metal cations being able to react with the acid groups of the polymer to form complexes. Examples of divalent or polyvalent metal cations are Mg ²⁺ , Ca ²⁺ , Al ³⁺ , Sc ³⁺ , Ti ⁴⁺ , Mn ²⁺ , Fe ²⁺ / ³⁺ , CO ²⁺ , Ni ²⁺ , Cu ⁺ / ²⁺ , Zn ²⁺ , Y ³⁺ , Zr ⁴⁺ , Ag ⁺ , La ³⁺ , Ce ⁴⁺ , Hf ⁴⁺ , and Au ⁺ / ³⁺ , preferred metal cations are Mg ²⁺ , Ca ^{2 +} , Al ³⁺ , Ti ⁴⁺ , Zr ⁴⁺ and La ³⁺ , and particularly preferred metal cations are Al ³⁺ , Ti ⁴⁺ and Zr ⁴⁺ . The metal cations can be used either alone or in a mixture with one another. Of the metal cations mentioned, all metal salts are suitable which have sufficient solubility in the solvent to be used. Metal salts with weakly complexing anions such as chloride, nitrate and sulfate are particularly suitable. Water, alcohols, DMF, DMSO and mixtures of these components can be used as solvents for the metal salts. Water and water / alcohol mixtures, such as water / methanol or water / 1,2-propanediol, are particularly preferred.

Spraying the metal salt solution onto the particles of the Hydrogel-forming polymer can be used both before and after Surface post-crosslinking of the particles take place. In one particular preferred method is the spraying of the metal salt solution in the same step as spraying the crosslinker solution, whereby both solutions are separated one after the other or simultaneously two nozzles are sprayed, or crosslinker and Metal salt solution can be sprayed together via a nozzle.

Optionally, a further modification of the hydrogel-forming polymers can be carried out by adding finely divided inorganic solids, such as, for example, silica, aluminum oxide, titanium dioxide and iron (II) oxide, which further enhances the effects of surface treatment. The addition of hydrophilic silica or of aluminum oxide with an average size of the primary particles of 4 to 50 nm and a specific surface area of 50-450 m ² / g is particularly preferred. The addition of finely divided inorganic solids is preferably carried out after the surface modification by crosslinking / complex formation, but can also be carried out before or during these surface modifications.

The surface post-crosslinked material is generally annealed.

Annealing, jacket temperature: 120-180 ° C, preferably 140-160 ° C, especially 150 ° C; Tempering, dwell time must match the temperature be adjusted, shorter at higher temperatures There are dwell times and longer ones with longer dwell times Post-crosslinking is present. Typical values are 150-10 minutes.

The AUL and CRC can be optimized through the post-crosslinking time become.

Copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides

Copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides are known and commercially available. Their manufacture is described in detail e.g. B. in US 5066742 and US 5026784, the manufacturing instructions are hereby part of the present invention.

Properties of the polymer mixtures according to the invention

The hydrogel-forming aqueous liquid absorbent Polymers generally have a particle size distribution of 10 µm to about 1000 µm, preferably about 100 µm to about 850 µm, in particular 150 microns to about 700 microns. In the above Size windows are preferably more than 80% by weight, in particular more like 90% by weight of the particles.

The odor-binding copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides generally have a particle size distribution of 10 μm to about 600 μm, preferably about 100 μm to about 400 μm, in particular 150 μm to about 300 μm. The size window mentioned preferably contains more than 80% by weight, in particular more than 90% by weight, of the particles.

The aqueous liquid-absorbing C ₂ -C ₈ olefin / anhydride, in particular maleic anhydride copolymer fibers are preferably obtained by the method according to US 5,026,784 Example 1 column 8 line 24 and have the properties described there (degree of neutralization 55%, diameter of the uncrosslinked 2-3 denier fiber.

The polymer blends show improved odor binding properties with high final absorption capacity, high gel strength and permeability, as well as high retention. Due to the presence of copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides, the products according to the invention have antimicrobial properties, so that an odor control system is based on them without the need to add further odor-inhibiting substances or odor-masking materials.

The addition of partially neutralized copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides in fiber form enables higher acquisition rates and higher retention values than is the case with the granular polymer mixture according to the invention.

In contrast to the prior art, in which an added Odor control unit for highly swellable polymers for waste leads to absorption performance, it occurs in the invention Polymer mixture for no negative influence on the Absorption profile. In addition, the inventive Products are manufactured much more cost-effectively because of Binder or other connection aids from Odor control unit can be dispensed with hydrogel-forming polymers.

The high absorption performance and an unchanged Absorption behavior of the hydrogel-forming polymers used enables longer wearing times when using the products according to the invention in Hygiene products. Skin irritation and skin irritation are caused by completely avoiding a constant pH environment and locked out.

Use and application of the polymer mixture

• A) eine obere flüssigkeitsdurchlässige Abdeckung
• B) eine untere flüssigkeitsundurchlässige Schicht
• C) einen zwischen (A) und (B) befindlichen Kern, enthaltend 10-100 Gew.-% des erfindungsgemäßem Polymerenmischung 0-90 Gew.-% hydrophiles Fasermaterial bevorzugt 20-100 Gew.-% des erfindungsgemäßem Polymerenmischung, 0-80 Gew.-% hydrophiles Fasermaterial mehr bevorzugt 30-100 Gew.-% des erfindungsgemäßem Polymerenmischung, 0-70 Gew.-% hydrophiles Fasermaterial noch mehr bevorzugt 40-100 Gew.-% des erfindungsgemäßem Polymerenmischung, 0-60 Gew.-% hydrophiles Fasermaterial besser bevorzugt 50-100 Gew.-% des erfindungsgemäßem Polymerenmischung 0-50 Gew.-% hydrophiles Fasermaterial besonders bevorzugt 60-100 Gew.-% des erfindungsgemäßem Polymerenmischung, 0-40 Gew.-% hydrophiles Fasermaterial insbesondere bevorzugt 70-100 Gew.-% des erfindungsgemäßem Polymerenmischung, 0-30 Gew.-% hydrophiles Fasermaterial außerordentlich bevorzugt 80-100 Gew.-% des erfindungsgemäßem Polymerenmischung, 0-20 Gew.-% hydrophiles Fasermaterial am meisten bevorzugt 90-100 Gew.-% des erfindungsgemäßem Polymerenmischung, 0-10 Gew.-% hydrophiles Fasermaterial
• D) gegebenenfalls eine sich unmittelbar oberhalb und unterhalb des Kerns (C) befindende Tissueschicht und
• E) gegebenenfalls eine zwischen (A) und (C) sich befindende Aufnahmeschicht.

The present invention further relates to the use of the above-mentioned polymer mixture in hygiene articles, comprising

• A) an upper liquid-permeable cover
• B) a lower liquid impermeable layer
• C) a core located between (A) and (B), containing 10-100% by weight of the polymer mixture according to the invention 0-90% by weight of hydrophilic fiber material, preferably 20-100% by weight of the polymer mixture according to the invention, 0-80% by weight % hydrophilic fiber material more preferably 30-100% by weight of the polymer mixture according to the invention, 0-70% by weight hydrophilic fiber material even more preferably 40-100% by weight of the polymer mixture according to the invention, 0-60% by weight hydrophilic fiber material more preferably 50-100% by weight of the polymer mixture according to the invention 0-50% by weight of hydrophilic fiber material, particularly preferably 60-100% by weight of the polymer mixture according to the invention, 0-40% by weight of hydrophilic fiber material, particularly preferably 70-100% by weight. % of the polymer mixture according to the invention, 0-30% by weight of hydrophilic fiber material extremely preferably 80-100% by weight of the polymer mixture according to the invention, 0-20% by weight of hydrophilic fiber material most preferably 90-100% by weight of the invention polymer mixture, 0-10% by weight of hydrophilic fiber material
• D) optionally a tissue layer located immediately above and below the core (C) and
• E) optionally a receiving layer located between (A) and (C).

All or part of the hydrophilic fiber material can be replaced by fiber material made from copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides. The percentages are to be understood such that at 10-100% by weight, 11, 12, 13, 14, 15, 16, 17, 18, 19 to 100% by weight of the polymer mixture according to the invention and all the% data in between (e.g. 12.2%) are possible and correspondingly hydrophilic fiber material from 0 to 89, 88, 87, 86, 85, 83, 82, 81% by weight and percentages in between (e.g. 87, 8%) are possible. If there are other materials in the core, the percentages of polymer and fiber decrease accordingly. The analog applies to the preferred areas, such as: B. with extreme preference can 81, 82, 83, 84, 85, 86, 87, 88, 89 wt.% For the inventive polymer mixture and correspondingly 19, 18, 17, 16, 15, 14, 13, 12, 11 wt -% of the fiber material is present. Thus, in the preferred range 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 to 100% by weight of polymer mixture according to the invention, in the more preferred range 30, 31, 32, 33, 34, 35, 36 , 37, 38, 39 to 100 wt .-% polymer mixture according to the invention, in the even more preferred range 40, 41, 42, 43, 44, 45, 46, 47, 48, 49 to 100 wt .-% polymer mixture according to the invention, in the better preferred range 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 to 100% by weight of polymer mixture according to the invention, in the particularly preferred range 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 to 100 wt .-% polymer mixture according to the invention, in the particularly preferred range 70, 71, 71, 72, 73, 74, 75, 76, 77, 78, 79 to 100 wt .-% polymer mixture according to the invention and most preferred Range 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100% by weight of polymer mixture according to the invention are present.

Hygiene articles include incontinence pads and Incontinence pants for adults as well as diapers for babies too understand.

The liquid-permeable cover (A) is around the layer that has direct skin contact. The material this consists of conventional synthetic or semi-synthetic fibers or films of polyester, polyolefins, rayon or natural fibers such as cotton. For non-woven materials the fibers are usually made of binders such as polyacrylates connect to. Preferred materials are polyester, rayon and their blends, polyethylene and polypropylene. examples for liquid permeable layers are described in WO 99/57355 A1, EP 102 388 3 A2.

The liquid-impermeable layer (B) usually exists from a film made of polyethylene or polypropylene.

The core (C) contains in addition to the invention Polymer blend of hydrophilic fiber material. Under is hydrophilic too understand that watery liquids quickly pass over the fiber to distribute. Usually the fiber material is cellulose, modified cellulose, rayon, polyester such as polyethylene terephthalate. Cellulose fibers such as cellulose are particularly preferred. The Fibers usually have a diameter of 1-200 µm, preferably 10-100 µm. In addition, the fibers have one Minimum length of 1 mm.

The structure and shape of diapers is well known and for example in WO 95/26 209 p. 66 line 34 to p. 69 Line 11, DE 196 04 601 A1, EP-A-0 316 518 and EP-A-0 202 127 described. Generally diapers and other hygiene items also in WO 00/65084, in particular on pages 6-15, WO 00/65348, especially on pages 4-17, WO 00/35502, especially pages 3-9, DE 197 37 434, WO 98/8439. Toiletries for the Feminine hygiene is described in the following references. The aqueous liquids polymer mixtures according to the invention can be used there. References for feminine hygiene: WO 95/24173: Absorption Article for Controlling Odor, WO 91/11977: Body Fluid Odor Control, EP 389023: Absorbent Sanitary Articles, WO 94/25077: Odor Control Material, WO 97/01317: Absorbent Hygienic Article, WO 99/18905, EP 834297, US 5,762,644, US 5,895,381, WO 98/57609, WO 2000/065083, WO 2000/069485, WO 2000/069484, WO 2000/069481, US 6,123,693, EP 1104666, WO 5 2001/024755, WO 2001/000115, EP 105373, WO 2001/041692, EP 1074233. Tampons are described in the following documents: WO 98/48753, WO 98/41179, WO 97/09022, WO 98/46182, WO 98/46181, WO 2001/043679, WO 2001/043680, WO 2000/061052, EP 1108408, WO 2001/033962, DE 200 020 662, WO 2001/001910, WO 2001/001908, WO 2001/001909, WO 2001/001906, WO 2001/001905, WO 2001/24729. Incontinence articles are described in the following writings: Disposable Absorbent Article for Incontinent Individuals: EP 311344 Description pp. 3-9; Disposable absorbent Article: EP 850623; Absorbent Article: WO 95/26207; Absorbent Article: EP 894502; Dry Laid Fibrous Structure: EP 850 616; WO 98/22063; WO 97/49365; EP 903134; EP 887060; EP 887059; EP 887058; EP 887057; EP 887056; EP 931530; WO 99/25284; WO 98/48753. Feminine hygiene and Incontinence articles are described in the following writings: Catamenial Device: WO 93/22998 description pp. 26-33; Absorbent members for Body Fluids: WO 95/26209 description pp. 36-69; Disposable Absorbent Article: WO 98/20916 Description pp. 13-24; Improved Composite Absorbent Structures: EP 306262 Description p. 3-14; Body waste absorbent Article: WO 99/45973. These references and the references there are hereby expressly included in the Disclosure of the invention included.

Alternatively, the core (C) can also consist of layers of the components (i) and (ii) exist. In principle, it can Multi-layer structures of 3 (e.g. layer of component (i) / layer of component (ii) / layer of component (i) or layer of component (ii) / layer of component (i) / layer of component (ii)), 4, 5 or more layers are present, but structures with are preferred two layers where both the layer with component (i) as well as with component (ii) can be closer to the body. Layer structures consisting of layers are also possible polymer mixtures according to the invention and layers of individual Components (i) and / or (ii).

The polymer mixtures according to the invention are suitable excellent as an absorbent for water and aqueous liquids, so that they are beneficial as a water retention agent in the agricultural horticulture, as a filtration aid and especially as an absorbent component in hygiene articles such as Diapers, tampons or sanitary napkins can be used.

Storage and fixation of the highly swellable invention polymer blends

In addition to the polymer mixture of hydrogel-forming polymers and copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides described above, compositions which contain the polymer mixture or to which it is fixed can be present in the absorbent composition according to the present invention. Any composition that can accommodate the polymer mixture and that can also be integrated into the absorption layer is suitable. A large number of such compositions are already known and have been described in detail in the literature. A composition for incorporating the polymer mixture can e.g. B. be a fiber matrix, which consists of a cellulose fiber mixture (airlaid web, wet laid web) or synthetic polymer fibers (meltblown web, spunbonded web), or consists of a mixed fiber structure made of cellulose fibers and synthetic fibers. Possible fiber materials are described in detail in the following chapter. The process of an airlaid web is described, for example, in WO 98/28 478. Open-pore foams or the like can also be used to incorporate the polymer mixture according to the invention.

Alternatively, such a composition can be created by fusing two Single layers are created, one or better a variety be formed in chambers containing the polymer mixture. Such a chamber system is described in detail in EP 0 615 736 A1 P. 7 line 26 ff.

In this case, at least one of the two layers should be be permeable to water. The second layer can either permeable to water or impermeable to water. As layer material can be tissue or other tissue, closed or open-pored foams, perforated films, elastomers or fabrics Fiber material are used. If the absorbent Composition consists of a composition of layers, the layer material should have a pore structure, the Pore dimensions are small enough to hold the particles of Retain polymer mixture. The above examples for the composition of the absorbent compositions also exclude laminates at least two layers with one between which the polymer mixture is installed and fixed.

Generally there is the possibility of the particles of the Polymer mixture within the absorbent core to improve the so-called Fix dry and wet integrity. Under dry and wet integrity one understands the ability to form highly swellable hydrogels in such a way to incorporate the absorbent composition that they outer Force effects both in the wet and in the dry state withstand and there is no displacement or leakage of highly swellable polymer comes. Under force are in front to understand everything mechanical loads, as in Sequence of movements occur when wearing the hygiene article, or else Weight load under which the hygiene article, especially in the Incontinence stands. There are a variety of fixings Possibilities that are known to the person skilled in the art. Examples like that Fixation by heat treatment, addition of adhesives, Thermoplastics, binder materials are listed in WO 95/26 209 p. 37 Line 36 to p. 41 line 14. Said passage is therefore Part of this invention. Methods of increasing wet strength can also be found in WO 2000/36216 A1.

Furthermore, the absorbent composition can consist of a Backing material, such as. B. consist of a polymer film on which the Polymer mixture is fixed. The fixation can both as well as on both sides. The carrier material can permeable to water or impermeable to water.

In the above compositions the absorbent composition will be Particles of the polymer mixture with a weight fraction of 10 up to 100% by weight, preferably 20-100% by weight, more preferably 30-100% by weight, even more preferably 40-100% by weight, more preferably 50-100% by weight, particularly preferably 60-100% by weight, in particular preferably 70-100% by weight, extremely preferably 80-100% by weight and most preferably 90-100 wt% based on the Total weight of the composition and the polymer blend built-in.

Fibrous materials of the absorbent composition

The structure of the present absorbent according to the invention The composition is based on diverse fiber materials that can be used as a fiber network or matrices. With Both fibers are included in the present invention natural origin (modified or unmodified), as well Synthetic fibers.

A detailed overview of examples of fibers used in of the present invention are patent WO 95/26 209 p. 28 line 9 to p. 36 line 8. Said passage is thus part of this invention.

Examples of cellulose fibers include those that commonly used in absorption products, such as Velcro pulp and cotton-type pulp. The materials (needle or Hardwoods), manufacturing processes such as chemical pulp, semi-chemical pulp, chemothermal mechanical pulp (CTMP) and bleaching processes are not particularly restricted. So find, for example, natural cellulose fibers such as cotton, Flax, silk, wool, jute, ethyl cellulose and cellulose acetate Application.

Suitable synthetic fibers are made from Polyvinyl chloride, polyvinyl fluoride, polytetrafluoroethylene, Polyvinylidene chloride, polyacrylic compounds such as ORLON ?, polyvinyl acetate, Polyethyl vinyl acetate, soluble or insoluble polyvinyl alcohol. Examples of synthetic fibers include thermoplastic Polyolefin fibers, such as polyethylene fibers (PULPEX®), Polypropylene fibers and polyethylene-polypropylene two-component fibers, Polyester fibers, such as polyethylene terephthalate fibers (DACRON® or KODEL®), copolyester, polyvinyl acetate, polyethyl vinyl acetate, Polyvinyl chloride, polyvinylidene chloride, polyacrylics, polyamides, Copolyamides, polystyrene and copolymers of the above Polymers, as well as two-component fibers Polyethylene terephthalate-polyethylene isophthalate copolymer, Polyethylene vinyl acetate / polypropylene, polyethylene / polyester, Polypropylene / polyester, copolyester / polyester, polyamide fibers (nylon), Polyurethane fibers, polystyrene fibers and polyacrylonitrile fibers. Polyolefin fibers, polyester fibers and their are preferred Two-component fibers. Also preferred are those adhering to heat Bicomponent sheath-core and polyolefin fibers Side-by-side type because of its excellent shape retention after liquid absorption.

The synthetic fibers mentioned are preferred in Combination with thermoplastic fibers used. In the The latter partially migrate into the matrix of the heat treatment existing fiber material and so make when cooling Connections and new stiffening elements. In addition, the means Addition of thermoplastic fibers an extension of the present Pore dimensions after heat treatment. In this way it is possible to continuously add thermoplastic fibers during the formation of the Absorbent layer the proportion of thermoplastic fibers towards the cover sheet continuously increasing, making an equally continuous Pore sizes increase. Thermoplastic fibers can be formed from a variety of thermoplastic polymers are preferred, which have a melting point of less than 190 ° C. between 75 ° C and 175 ° C. At these temperatures is still no damage to the cellulose fibers to be expected.

Lengths and diameters of those described above Synthetic fibers are not particularly limited and, in general, can any fiber with a length of 1 to 200 mm and one Diameter from 0.1 to 100 denier (grams per 9,000 meters) are preferably used. Preferred thermoplastic fibers have a length of 3 to 50 mm, particularly preferred a length of 6 up to 12 mm. The preferred diameter of the thermoplastic Fiber is between 1.4 and 10 decitex, particularly preferred between 1.7 and 3.3 decitex (grams per 10,000 meters). The shape is not particularly restricted and examples close fabric-like, narrow cylinder-like, cut / split yarn-like, staple and continuous fiber.

The fibers in the absorbent according to the invention Composition can be hydrophilic, hydrophobic or a combination of both be both. As defined by Robert F. Gould in the Publication "Contact Angle, Wettability, and Adhesion", American Chemical Society (1964) calls a fiber hydrophilic when the contact angle between the liquid and the fiber (or its surface) is less than 90º, or if the Liquid tends to spread spontaneously on the same surface. As a rule, both processes are coexistent. Conversely a fiber is said to be hydrophobic if a contact angle of is formed larger than 900 and no spreading is observed.

Hydrophilic fiber material is preferably used. Especially fiber material is preferably used, that to the body side weakly hydrophilic and in the region around the polymer mixture is most hydrophilic. In the manufacturing process, the Using layers of different hydrophilicity a gradient which generates the impinging liquid to the hydrogel channeled where the absorption ultimately takes place.

Suitable hydrophilic fibers for use in the absorbent composition according to the invention are, for example Cellulose fibers, modified cellulose fibers, rayon, Polyester fibers such as B. polyethylene terephthalate (DACRON®), and hydrophilic nylon (HYDROFIL®). Suitable hydrophilic fibers can also are obtained by hydrophilizing hydrophobic fibers, such as z. B. the treatment of thermoplastic fibers obtained from Polyolefins (such as polyethylene or polypropylene, polyamides, Polystyrenes, polyurethanes, etc.) with surfactants or silica. Out However, for reasons of cost and availability Cellulose fibers preferred.

The polymer mixture is in the fiber material described embedded. This can be done in a variety of ways, e.g. B. together with the polymer material and the fibers Absorbing layer builds up in the form of a matrix, or by embedding that of the polymer particle mixture in layers of fiber mixture, where they are ultimately fixed, either by adhesive or Lamination of the layers.

The liquid-absorbing and -distributing fiber matrix can thereby from synthetic fiber or cellulose fiber or a Mixture of synthetic fiber and cellulose fiber, where the mixing ratio of (100 to 0) synthetic fiber: (0 to 100) cellulose fiber can vary. The used Cellulose fibers can be used to increase the dimensional stability of the Hygiene items must also be chemically stiffened.

The chemical stiffening of cellulose fibers can different ways can be achieved. For one, one can Fiber stiffening can be achieved by adding suitable ones Coatings / coatings to the fiber material. Such additives close e.g. polyamide-epichlorohydrin coatings (Kymene® 557 H, Hercoles, Inc. Wilmington Delaware, USA), polyacrylamide coatings (described in U.S. Patent 3,556,932 or as a commercial product of Parez® 631 NC, American Cyanamid Co., Stamford, CT, USA), With melamine-formaldehyde coatings and polyethyleneimine coatings on.

The chemical stiffening of cellulose fibers can also be done by chemical reaction. So z. B. the addition of suitable crosslinking substances bring about a crosslinking that takes place within the fiber. Suitable crosslinking substances are typical substances that are used to crosslink monomers. Included, but not limited to, are C ₂ -C ₈ dialdehydes, C ₂ -C ₈ monoaldehydes with acid functionality, and in particular C ₂ -C ₉ polycarboxylic acids. Specific substances from this series are, for example, glutaraldehyde, glyoxal, glyoxylic acid, formaldehyde and citric acid. These substances react with at least 2 hydroxyl groups within a single cellulose chain or between two adjacent cellulose chains within a single cellulose fiber. The crosslinking stiffens the fibers, which are given greater dimensional stability through this treatment. In addition to their hydrophilic character, these fibers have uniform combinations of stiffening and elasticity. This physical property makes it possible to maintain the capillary structure even with simultaneous contact with liquid and compression forces and to prevent premature collapse.

Chemically crosslinked cellulose fibers are known and in WO 91/11162, U.S. Patent 3,224,926, U.S. Patent 3,440,135, U.S. U.S. Patent 3,932,209 Patent 4,035,147, U.S. Patent 4,822,453, U.S. U.S. Patent 4,888,093, U.S. U.S. Patent 4,898,642 and U.S. patent 5,137,537. Chemical crosslinking causes one Stiffening of the fiber material, which ultimately results in one improved dimensional stability of the entire hygiene article reflects. The individual layers are made by a person skilled in the art known methods, such as B. fusion by heat treatment, Add hot melt adhesives, latex binders etc. to each other connected.

Manufacturing process of the absorbent composition

The absorbent composition is composed Compositions containing the polymer blend and the Polymer mixture present in or on said compositions is fixed.

Examples of methods by which an absorbent Receives composition, for example, from a Carrier material exist on the one or both sides of the particles Polymer mixtures are fixed, are known and of the invention included, but not limited to.

Examples of methods by which an absorbent Receives composition, for example, from in one Fiber material mixture of synthetic fibers (a) and cellulose fibers (b) embedded polymer mixture (c), the Mixing ratio of (100 to 0) synthetic fiber: (0 to 100) Cellulose fiber may vary, including (1) a process which (a), (b) and (c) are mixed simultaneously, (2) Process in which a mixture of (a) and (b) is mixed into (c) (3) a method in which a mixture of (b) and (c) with (a) is mixed, (4) a process in which a mixture of (a) and (c) mixed into (b), (5) a process in which (b) and (c) are mixed and (a) is metered in continuously, (6) a method in which (a) and (c) are mixed and (b) is metered in continuously, and (7) a process in which (b) and (c) mixed separately into (a). Of these For examples, methods (1) and (5) are preferred. The Device used in this process is not special limited and it can be a conventional one known to the person skilled in the art Device can be used.

The correspondingly produced absorbent composition can optionally subjected to heat treatment so that a Absorbent layer with excellent dimensional stability in damp Condition results. The heat treatment procedure is not particularly restricted. Examples include heat treatment by supplying hot air or infrared radiation. The The temperature during the heat treatment ranges from 60 ° C to 230 ° C, preferably between 100 ° C and 200 ° C, particularly preferred between 100 ° C and 180 ° C.

The duration of the heat treatment depends on the type of synthetic fiber, its quantity and the production speed of the Hygiene article. Generally the duration of the heat treatment is between 0.5 seconds to 3 minutes, preferably 1 second to 1 Minute.

The absorbent composition is generally for example with a liquid-permeable cover layer and provided with a liquid-impermeable underlayer. Furthermore, leg cuffs and adhesive tapes are attached and so on the hygiene article completed. The materials and types of permeable top layer and impermeable bottom layer, as well the leg ends and adhesive tapes are known to the person skilled in the art and not particularly restricted. Examples of this can be found in WO 95/26 209.

test methods a) Centrifuge retention capacity (CRC Centrifuge Retention Capacity)

This method determines the free swellability of the polymer mixture in the tea bag. To determine the CRC, 0.2000 ± 0.0050 g of the polymer mixture according to the invention, e.g. B. dry polymer mixture consisting of 0.18 g hydrogel-forming polymer (grain fraction 106-850 µm) and 0.02 g copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides (grain fraction 100-400 µm) in a 60 × 85 mm tea bag weighed, which is then welded. The tea bag is placed in an excess of 0.9% by weight saline solution (at least 0.83 l saline solution / 1 g polymer powder) for 30 minutes. The tea bag is then centrifuged at 250 g for 3 minutes. The amount of liquid is determined by weighing the centrifuged tea bag.

To determine the CRC in the comparison tests is used instead the hydrogel-forming polymer alone in the polymer mixture used (0.2000 ± 0.0050 g).

b) Absorption under pressure (AUL Absorbency Under Load) (0.7 psi)

The measuring cell for determining the AUL 0.7 psi is a plexiglass cylinder with an inner diameter of 60 mm and a height of 50 mm, which has a glued-on stainless steel sieve bottom with a mesh size of 36 µm on the underside. The measuring cell also includes a plastic plate with a diameter of 59 mm and a weight, which can be placed together with the plastic plate in the measuring cell. The weight of the plastic plate and the total weight are 1345 g. To carry out the determination of the AUL 0.7 psi, the weight of the empty plexiglass cylinder and the plastic plate is determined and noted as Wo. Then 0.900 ± 0.005 g of a polymer mixture according to the invention, z. B. Polymer mixture consisting of 0.81 g hydrogel-forming polymer (grain fraction 106-850 µm) and 0.09 g copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides (grain fraction 100-400 µm) weighed into the plexiglass cylinder and as evenly as possible distributed to the stainless steel sieve bottom. Then the plastic plate is carefully placed in the plexiglass cylinder and the entire unit is weighed; the weight is noted as W _a . Now the weight is placed on the plastic plate in the plexiglass cylinder. In the middle of the Petri dish with a diameter of 200 mm and a height of 30 mm, a ceramic filter plate with a diameter of 120 mm and a porosity of 0 is placed and 0.9% by weight sodium chloride solution is filled in so that the liquid surface is flush with the filter plate surface, without wetting the surface of the filter plate. A round filter paper with a diameter of 90 mm and a pore size <20 µm (S&S 589 black tape from Schleicher & Schüll) is then placed on the ceramic plate. The plexiglass cylinder containing the polymer mixture is now placed with the plastic plate and weight on the filter paper and left there for 60 minutes. After this time, the complete unit is removed from the Petri dish from the filter paper and then the weight is removed from the Plexiglas cylinder. The plexiglass cylinder containing the swollen hydrogel mixture is weighed together with the plastic plate and the weight is noted as W _b .

The absorption under pressure (AUL) is calculated as follows:

AUL 0.7 psi [g / g] = [W _b - W _a ] / [W _a - W ₀ ]

The AUL 0.5 psi comes with a correspondingly reduced weight measured on the plastic plate.

To determine the AUL 0.7 psi or 0.5 psi for the Comparative experiments will instead of the polymer mixture Hydrogel-forming polymer used alone (0.9000 ± 0.005 g).

c) Saline Flow Conductivity (SFC)

The test method for determining the SFC is described in U.S. 5 599 335.

d) Measurement of the pH of the hydrogel-forming polymers

100 ml 0.9% by weight NaCl solution are in one 150 ml beaker with the help of a magnetic stirrer at moderate speed stirred, so that no air into the solution by stirring is drawn in. 0.5 ± 0.001 g of the solution are added to this solution measuring polymer and stirred for 10 minutes. After 10 minutes the pH of the solution is measured using a pH glass electrode, whereby the value is only read when it is stable, at the earliest after 1 minute.

e) Measurement of the buffer capacity of the hydrogel-forming polymers

To determine the buffer capacity of the hydrogel-forming Polymers were 0.5 ± 0.001 g hydrogel-forming polymer or Polymer mixture in 100 ml 0.9% by weight NaCl solution in a 150 ml Beaker submitted and using a magnetic stirrer agitated moderate speed, so that by stirring no Air is drawn into the solution. After 10 minutes the pH Value of the solution for the first time with the help of a pH glass electrode measured, whereby the value is only read when it is stable, at the earliest after 1 minute. In the following 0.1 molar NaOH solution added so that every 5 minutes 0.05 ml of 0.1 molar NaOH solution were metered in with further stirring. in the During the addition, the pH of the mixture became steady checked. The pH was evaluated before adding 0.1 molar NaOH solution and the pH after 6 hours.

Examples

Draw the polymer mixtures obtained in the examples in contrast to those obtained in the comparative examples Polymers through a combination of absorption quantity and Swelling speed and show a high Liquid permeability, as well as improved odor binding properties. she are therefore excellent as absorbents for Water and aqueous liquids, especially of Body fluids such as B. urine or blood, suitable, for example in hygiene articles such as B. baby and adult diapers, Sanitary napkins, tampons and the like.

The following examples are intended to explain the invention in more detail.

Comparative Example 1

• a) In a 40 l plastic bucket, 6.9 kg of pure acrylic acid Diluted 20 kg of deionized water. Adds to this solution 33 g of pentaerythritol triallyl ether are added with stirring, and inertizes the closed bucket by passing it through Nitrogen. The polymerization is then carried out by adding 0.4 g hydrogen peroxide, dissolved in 40 ml deionized Water, and 0.2 g ascorbic acid dissolved in 40 ml deionized Water, started. After the reaction is complete, the gel mechanically crushed and mixed with as much sodium hydroxide solution until a degree of neutralization of 75 mol% based on the used acrylic acid is reached. The neutralized gel is then dried on a drum dryer, with a Pin mill ground, and finally at 150-850 µm sieved.
• b) The base polymer produced under a) was in a Lödige Laboratory mixer with, based on base polymer, 2.9% by weight Crosslinker solution, composed of 49.56 parts by weight Propanediol-1.2 49.56 parts by weight of deionized water and 0.88 parts by weight of monoethylene glycol diglycidyl ester (EDGE) sprayed. The moist product was then in transferred a second preheated Lödige laboratory mixer and annealed at 140 ° C for 60 minutes. The dried and on Product cooled to room temperature was sieved at 850 μm.

Comparative Example 2

• a) In a 40 l plastic bucket, 6.9 kg of pure acrylic acid Diluted 20 kg of deionized water. Adds to this solution 33 g of pentaerythritol triallyl ether are added with stirring, and inertizes the closed bucket by passing it through Nitrogen. The polymerization is then carried out by adding 0.4 g hydrogen peroxide, dissolved in 40 ml deionized Water, and 0.2 g ascorbic acid dissolved in 40 ml deionized Water, started. After the reaction is complete, the gel mechanically crushed and mixed with as much sodium hydroxide solution until a degree of neutralization of 75 mol% based on the used acrylic acid is reached. The neutralized gel is then dried on a drum dryer, with a Pin mill ground, and finally at 150-850 µm sieved.
• b) The base polymer produced under a) was in a Lödige Laboratory mixer with, based on base polymer, 3.75% by weight Crosslinker solution, composed of 33.3 parts by weight Propanediol-1.2 63.5 parts by weight of deionized water and 3.2 parts by weight of EDGE and 0.12 parts by weight sprayed with a 27% aqueous aluminum sulfate solution. Crosslinker solution and aluminum sulfate solution are separated from each other, but sprayed simultaneously via 2 nozzles. Then the wet product was in a second preheated Lödige laboratory mixer transferred and at 140 ° C for 60 Minutes annealed. The dried and at room temperature cooled product was sieved at 850 microns.

Comparative Example 3

In a polyethylene vessel with a capacity of 10 l, well insulated by foamed plastic material, 3928 g of demineralized water are placed, 625 g of sodium hydrogen carbonate are suspended therein and 2000 g of acrylic acid are allowed to flow in with stirring so that no foaming occurs due to the onset of CO ₂ evolution. An emulsion of 1.3 g of sorbitan monococoate in 100 g of demineralized water and 8.1 g of allyl methacrylate are added in succession and the solution is further rendered inert by introducing nitrogen. The initiator system, consisting of 1.66 g of 2,2'-azobisamidinopropane dihydrochloride, dissolved in 20 g of demineralized water, 3.33 g of potassium peroxodisulfate, dissolved in 150 g of demineralized water and 0.3 g of ascorbic acid, is then added. dissolved in 25 g of demineralized water in succession with stirring. The reaction solution is then left to stand without stirring, a solid gel being formed as a result of the polymerization which begins, in the course of which the temperature rises to approximately 90.degree. This is mechanically shredded using a meat grinder and dried in a forced-air drying cabinet on a sieve made of VA wire at temperatures of 160 ° C, then ground and sieved.

Comparative Example 4

TYLOSE VS 3790, a super absorber from CASSELLA AG-Frankfurt am Main, characterized by a pH of 5-5.5 Analogously to Example 7 of EP 0 316 792 B1, in a 20 g scale WARING blender (modified attachment for kitchen mixer) with a surface post-crosslinking solution (from 2 ml Syringe sprayed), consisting of 2.3% water / 1.2% Propanediol 1.2 / 0.2% ethylene glycol diglycidyl ether (each based on polymer) and 1 hour at 140 ° C in one Circulating air oven tempered.

Comparative Example 5

In an absolutely evacuated to 980 mbar using a vacuum pump Laboratory kneader with a working volume of 2 l (WERNER + PFLEIDERER) is one that was previously manufactured separately. 25 ° C cooled and rendered inert by introducing nitrogen Monomer solution sucked in. The monomer solution settles as follows together: 825.5 g demineralized water, 431 g acrylic acid, 120.68 g NaOH 50%, 0.86 g polyethylene glycol 400 diacrylate (SARTOMER® 344 der CRAY VALLEY company) The kneader is used for better inerting evacuated and then vented with nitrogen. This The process is repeated 3 times. Then a solution of 1.2 g Sodium persulfate, dissolved in 6.8 g demineralized water and after another 30 Seconds another solution consisting of 0.024 g Ascorbic acid, dissolved in 4.8 g of demineralized water. It will be with Nitrogen purged. A jacket heating circuit preheated to 75 ° C (Bypass) is switched to the mixer bowl, the stirrer speed increased to 96 rpm. After the onset of polymerization and reaching from Tmax the jacket heating circuit is switched back to bypass and polymerized for 15 minutes without heating / cooling, then cooled, the product discharged. and the resulting ones Gel particles on sheets with wire mesh base at 160 ° C in Circulating air drying cabinet dried, then ground and sieved.

1200 g of the product thus obtained with a particle size distribution of 105-850 μm were in a powder mixing unit (Loedige mixer) a homogeneous solution consisting of 17.58 g water, 9.96 g 1,2-propanediol, 1.2 g of ethylene glycol diglycidyl ether and 3.36 g sprayed a 26.8% aqueous aluminum sulfate solution, in a preheated and 2. Lödige mixer. Under constant conditions at a jacket temperature of 150 ° C and one Revolutions of 60 rpm, the tempering took place over a Period of 70 minutes. The mixer has been emptied, the product cooled down to room temperature and sieved at 850 µm.

example 1

Parts of powder of the copolymer i-butylene / maleic anhydride (1/1) from Kuraray Isoprene Chemical Company, Ltd ,. (Tokyo, Japan, trademark: ISOBAM®) and 95 parts from comparative example 4 are homogeneous in a laboratory tumble mixer for 60 minutes mixed.

Example 2

10 parts powder of the copolymer i-butylene / maleic anhydride (1/1) Kuraray Isoprene Chemical Company, Ltd ,. (Tokyo, Japan, trademark: ISOBAM®) and 90 parts from comparative example 4 are homogeneous in a laboratory tumble mixer for 60 minutes mixed.

Example 3

Parts of powder of the copolymer i-butylene / maleic anhydride (1/1) from Kuraray Isoprene Chemical Company, Ltd ,. (Tokyo, Japan, trademark: ISOBAM®) and 95 parts from comparative example 2 are homogeneous in a laboratory tumble mixer for 60 minutes mixed.

Example 4

Parts of powder of the copolymer i-butylene / maleic anhydride (1/1) from Kuraray Isoprene Chemical Company, Ltd ,. (Tokyo, Japan, trademark: ISOBAM®) and 90 parts from comparative example 2 are homogeneous in a laboratory tumble mixer for 60 minutes mixed.

Example 5

50 parts powder of i-butylene / maleic anhydride Copolymer fibers, produced according to method US 5,026,784 Example 1 column 8 Lines 24 and 50 parts from Comparative Example 1 are in one Laboratory tumbler mixer homogeneously mixed for 60 minutes.

The performance data of the examples for the absorption performance can be found in Table 1, the odor binding properties are approximated in Table 2 with the measured value pH after 6 hours (buffer capacity). Table 1

Table 2

The results show that the examples according to the invention approximately the same performance in terms of absorption performance have a significantly improved odor binding. The latter could in the test due to the enormous buffer capacity during the titration 0.1 molar NaOH solution can be shown. Comparative Example 3 and Comparative Example 5 have a lower pH than Example 1 and 2 also have good odor control; the performance everything regarding the CRC is however clearly worse.

Comparative Examples 1 and 2 are Hydrogel-forming material from the prior art, which at pH values of 5.95 and 6.1, especially with regard to the absorption performance is optimized under pressure load while the Odor-binding properties (buffer capacity) are moderate. Will this material however mixed with copolymer fibers (here in a ratio of 1: 1 with comparative example 1), there are increases in retention to recognize.

Claims (11)

1. Polymer mixtures comprising the components (i) hydrogel-forming polymers which absorb aqueous liquids, prepared by polymerizing olefinically unsaturated carboxylic acids or their derivatives, and (ii) copolymers of C ₂ -C ₈ olefins or styrenes with anhydrides. 2. Polymer mixtures according to claim 1, wherein component (i) is granular or fibrous and component (ii) regardless of this is granular or fibrous and optionally component (ii) additionally fibrous or is granular. 3. Polymer mixtures according to claim 1, wherein component (ii) sprayed onto component (i) as a polymer or as Momomer mixture is sprayed on with subsequent Polymerization. 4. Polymer mixtures according to one of claims 1 to 3, wherein the Component (i) is based on polyacrylate. 5. Polymer mixtures according to one of claims 1 to 4, wherein the Component (ii) is in granular form. 6. Polymer mixtures according to one of claims 1 to 5, wherein the Component (ii) is unsaponified. 7. Polymer mixtures according to one of claims 1 to 6, wherein the Anhydride component of component (ii) maleic anhydride and the olefinic or styrene component is selected one or more of the following compounds: Isobutylene, vinyl acetate, ethylene or styrene. 8. Polymer mixtures according to one of claims 1 to 7, wherein the Component (i) as a grafted product, especially on Carboxymethyl cellulose. 9. Polymer mixtures according to one of claims 1 to 8, wherein the Component (i) 99.7% by weight to 85% by weight and the Component (ii) is present at 0.3% by weight to 15% by weight. 10. Hygiene articles containing polymer mixtures according to one of the Claims 1 to 9. 11. Use of polymer mixtures according to one of claims 1 to 9 as an absorbent for aqueous liquids reduced odor.